Hi Peter, I can't be bothered fiddling around so here's a link to my Flickr with pictures of the top and the guitar getting a good testing. I'm out playing again tonight so I'll get Gerry or someone to get some pictures of it in action at the Labour Club. https://www.flickr.com/photos/26072650@N03/

So, you have a carbon rod that connects the top to the back under the bridge? If so, that is pretty much a "soundpost" just like in a violin, and that has been tried many times but is generally seen as a tone killer because it will couple the top to the back and deaden and hamper the top. And be careful about the "name" thing, just because you have heard of someone before (or not) is no measure of the BS meter. I have met some of the big names and found the BS factor to be high, and the opposite to be true for others I know and I can vouch for Barry.

Mark Swanson wrote:So, you have a carbon rod that connects the top to the back under the bridge? If so, that is pretty much a "soundpost" just like in a violin, and that has been tried many times but is generally seen as a tone killer because it will couple the top to the back and deaden and hamper the top. And be careful about the "name" thing, just because you have heard of someone before (or not) is no measure of the BS meter. I have met some of the big names and found the BS factor to be high, and the opposite to be true for others I know and I can vouch for Barry.

I refer only to luthiers I do not know personally but who have been helpful in replying to emails, which I think is pretty good for a busy luthier. Whether you can vouch for Barry is immaterial, his comments were not at all positive or supportive and merely sounded bossy, ill mannered and from a know it all. The soundpost idea may well be a tone killer in certain circumstances but why does it work in a violin, then? Perhaps it was used in relation to a normally braced guitar top, when I can imagine it would add to the deadening effect of the x bracing, because that effect does happen. In fact I now believe the cleverest part of the Martin x bracing was in the way it evened out the wide range of frequencies produced by a guitar defining each one, but in my opinion for the loss of harmonics/ complementary vibrations. You would have to try a free floating top to see the difference in volume and tone/harmonics. If anyone who reads this is not sure about trying an experimental guitar then Boulder Creek have produced a range of suspended bracing guitars that are proving very successful indeed. I quote from their website. "It seemed that if the bridge could be secured without using traditional X-type wood bracing, the top would vibrate more freely. This would allow greater sustain, volume, and an overall richer tone." The designers were right.I wasn't aware of their products when I began my experimentation, which is why I use entirely different materials and suspension methods. The soundpost is one idea, and far from being a sound deadener, because of design reasons and changes in back bracing it adds a deeper bass, partly because the section of the back which the soundpost is attached to is the part which is free of the body when playing. What no one seems to have mentioned in this thread is integral strength. Past developments were entirely based around the then available materials and their strengths and weaknesses. Modern materials offer greater strength to weight ratios when used properly and I believe offer the opportunity to improve the tone of guitars at reasonable cost without employing expensive and increasingly rare tonewoods. The first two guitars I built with floating tops (after quite a few standard guitars) used pre formed laminate back and sides for cost effectiveness, yet sound almosty as good, and perhaps slightly better, than standard braced guitars. Certainly they hold their own in the company of guitars costing in the thousands, and you can believe me when I say that I take them out for other guitarists to try, some of whom own some very desirable guitars indeed. The new guitar has solid tonewood back and sides, and so far is proving to be a worthwhile investment in time and money. I wish Peter the very best in his ideas...he can always make standard guitars alongside the experimental ones, and people should remember that at one time the X bracing system was revolutionary and I expect it was condemned by those with a vested interest in the ladder bracing technology they understood. Developments in new materials will bring changes, and those that make it through to the production lines will rapidly become the norm. Who knows when Martin, or Taylor, or Collings or Gibson or Fender will anounce a new carbon braced guitar with a fuller tonal range....tomorrow perhaps, whereupon they will become the new norm.

Charlie Schultz wrote:Ease up guys- to quote one of our rules "We take the "be polite" rule VERY seriously - we do not tolerate ANY rudeness, or any messages that constitute a personal attack."

What set this off was a post, which has since been deleted, that was certainly rude and could be considered a personal attack, and to which Dave originally responded. I have received an apology for this, so let's let bygones be bygones and move on. This is the "Try Something New" challenge, so lets not have any more general comments about how people who are trying new ideas should stick to the old ways.

Any constructive (even harsh) criticism and suggestions are certainly welcomed, but try to be as specific as possible. And if you're responding to a post somewhere up the line, please quote it so we know what you are responding to.

My posts were out of line considering the section we are in. But they were in no way a personal attack. I was trying to provide constructive criticism. By the way Peter, you came across a lot more polite in your PM. I do not appreciate your last remark. It is this kind of crap that makes me want to get off the internet. I am done with trying to help newbies. Done!

Barry, when someone tells me that I have no business trying something new until I've mastered the old ways, true as that may be, I construe that as a personal attack. I tried to be polite in my PM to patch things up, even saying that I could understand how you felt because of my own personal experience in my own career. I now see that you understand it was not appropriate to post those comments in this thread, and you did so mistakenly, and apologized for it, and I hold no animosity toward you.

I'm assuming you're upset about the "so lets not have any more general comments about how people who are trying new ideas should stick to the old ways" remark. I was not directing that at you, but just mentioning it because those kinds of comments are not helpful in working toward trying to improve the sound of the guitar - I need specific recommendations, such as "try putting some braces here and here to do such and such to the sound". I'm sorry if you took it personally - it was certainly not meant that way.

Additionally, I am realizing more and more that I am not a good fit for this forum, helpful though it has been, but be that as it may I will continue this thread until the challenge is over. Again, any specific comments and criticisms are welcome.

Peter there isn't really any 'good fit' for any forum. The right way is to filter the good advice from the unhelpful... but don't be afraid to stand your ground if you have something you want to do and you feel 'put down' by someone else. If it you would like to to see me when I really get annoyed try asking if you can borrow my Japanese chisels, or use my workshop. Of course one also has to sometimes admit that things can go wrong, like when my attempt to walk across the Channel to France ended very wetly. It's also worth remembering that Stradivarius and Guarneri (spelling?) the famous violin makers had many disciples, who are now all known as 'from the school of'. That would be because the students all continued to make violins but only in the exact way that they had been taught, with no variation or improvement and so never contributed to the development of the instrument. I'm sure that anyone looking at my guitars will find many flaws, and not least in the finish, but that would be because I will not use filler and epoxy resins to make a gloss. I like to use the thinnest possible finish to preserve the natural qualities of the wood, and as far as possible use naturally based products. As a result small minor flaws that in other guitars would be covered up are visible. It's a price I have to pay, and I think its worth it. Others may disagree and they will make fine guitars too. That's good as the buyer has a choice.Which reminds me, Mark Swanson mentioned the soundpost idea, which I have used in my new guitar, but no one has pinted out the fundamental difference between playing a violin and playing a guitar which is the reason for the effectiveness of a soundpost in a violin. The violin is bowed, and the bow continually puts new energy into the violin through the strings, thus the soundpost does not 'deaden' the tone it continually renews it. I'm surprised nobody pointed that out before. In a guitar with a specially braced back the soundpost amplifies the bass particularly at the moment of initial attack, when the plectrum or fingers move the strings and put new energy into them. The soundpost then contributes to the overall bass sound for that short period, and also every time the string is struck. This bass response is quite precise and certainly different from a 'booming' bass. The guitar is still less than a fortnight old but no one has found the sound unpleasant, quite the opposite. I will need to play it, and let others play it some more before I can properly put into words what the difference is. In fact, I might have to build another guitar of exactly the same materials but put in a removeable tone bar so that it can be compared with and without tone bar.....and that, I suppose, is the only drawback with experimenting.... there may be no end to it.

Ansd finally, unless I get any more notifications that this thread continues, Peter, I've been at a loose end after finishing the last experimental guitar, so it's been time to decide which direction to take my guitar building and I have decided for the next two years at least to concentrate on developing and expending my knowledge of carbon fibre bracing.

Peter, in your picture "strut torqued" posted June 9, it looks like the component failing under the rotation of the bridge is the blocks holding the carbon fiber, not the carbon fiber. Sort of like trying to hold a fishing pole with your fingertips. If the extra couple CF tubes are helping, it's probably because the load is distributed in the blocks better.

Since what you're doing is sort of a backwards Bridge Doctor (as I think someone mentioned before), you might as well take a tip from their construction: the bridge attachment component is basically a single, solid piece of wood. If you used CF bars and attached them directly to the bridge blocks (you could even splay them out to avoid the soundhole and anchor them somewhere in the upper bout), you'd have a stronger structure that is less prone to deformation.

Jason, thanks for your suggestions. You are right that the failure at the bridge was in the maple blocks, not the carbon fiber. I just had them tightly press fit in the holes. The double ones are epoxied in, after treating the holes themselves with CA, and seem to be holding fine.

However, I think they are too stiff and inhibit the motion of the bridge too much. Maybe by using aluminum I could get back to the single rod, which might give more vibrational flexibility but be strong enough to hold the top flat. I considered using a single block like the Bridge Doctor does, but I wanted to see if adjusting the tension separately on the treble and bass rods would make a difference in the frequency response of the top. I've still to evaluate that.

Jason Rodgers wrote:If you used CF bars and attached them directly to the bridge blocks (you could even splay them out to avoid the soundhole and anchor them somewhere in the upper bout), you'd have a stronger structure that is less prone to deformation.

If I'm understanding you correctly, I think this would lose most of the torque counteracting that of the strings to keep the top flat.

So my next step is to string with medium gauge strings (ordered but not arrived) and compare the output against the lights. Then try some thin, short braces on the treble side of the lower bout to see if this helps the treble response, such as this:

I should be able to evaluate that with the spectrograms and Chladni patterns, not to mention my own ears.

Next, I will make a new bridge with the lowest mass possible, and try to attach low mass but slightly flexible struts. The current bridge and saddle weigh 40g - way too much.

I've also ordered some books to help me through this (not the expensive ones, yet.)

Peter Wilcox wrote:If I'm understanding you correctly, I think this would lose most of the torque counteracting that of the strings to keep the top flat.

Maybe. I dunno. I was thinking something like this...

The rectangular CF bars (3/8" x 1/8") would anchor somewhere on the sides of the upper bout (requiring some blocks be glued in), and the bridge anchor blocks would be lower in profile to give them more strength to hold the CF bars.

If I'm understanding the mechanics of this sort of setup, the Bridge Doctor uses compression to hold the bridge flat (front edge of the bridge rotating down, Bridge Doctor bridge anchor presses against rod, rod presses against tail block), while your solution uses tension (back edge of the bridge rotating up, Wilcox Doctor bridge anchor pulls against rod, rod is glued into head block). No qualitative analysis there, just observation.

I think going in and adding braces is a good idea. There's a great "Meet the Maker" article in the latest AL about French builder Olivier Fanton d'Andon who arrived at his current bracing system (looks a lot like the Kasha pattern!) by starting with an unbraced top, strung up, and gradually added and subtracted braces to the outside until he got the sound he wanted.

I didn't realize your idea raised the height of the bridge block as in the Bridge Doctor, which would give it adequate torque. I'll try that if my other methods aren't strong enough, though making it a solid block might add to the mass of the bridge, which I think I need to minimize as much as possible.

The long CF rods are not glued to the heel block, but are attached to a wooden cross member which has bolts that go through holes in the block on each side of the heel. These are adjusted by sex screws (hollow screws with an inside thread like a nut) from the outside of the guitar to vary the tension of the pull on the CF rods and thence on the bridge. I'm hoping that by varying the treble and bass tensions I can modify the sound of the guitar to some degree.

It looks like this challenge has died with no completions, as I understood it was supposed to end yesterday.

I'm still working on my instrument, though with lots of interruptions. I tried nylon strings - a complete bust, unable to drive the top. Medium gauge steel strings made some improvement in volume. I've now made a lighter bridge, and a new strut system. I wanted to try to make the top more flexible at the bridge, so reverted to a single vertical strut on each side. I've used aluminum blocks to keep the weight down, and to keep the struts from digging in to the block, as they were doing in the maple ones.

The volume has improved, but the CF is too flexible in the length I have it, and can't keep the top flat. So the next step is to start shortening them until the top stays flat, but will hopefully be flexible enough not to kill the sound - a fine balance. After that I'll try the short braces on the treble side of the bridge.